New derivatives of sulfonyl-, sulfinyl- and sulfenyl-1H-pyrazolo {8 3,4-b{9 -pyridines

ABSTRACT

The novel compounds are useful as central nervous system depressants, antiinflammatory and diuretic agents. In addition, the new compounds increase the intracellular concentration of adenosine-3&#39;&#39;,5&#39;&#39;-cyclic monophosphate. The new derivatives of sulfonyl-, sulfinyl- and sulfenylpyrazolo(3,4-b)pyridines have the general formula

United States Patent 11 1 Denzel et al.

[73] Assignee: E. R. Squibb & Sons, Inc.,

Princeton, NJ.

22 Filed: Mar. 29, 1974 21 Appl.No.: 456,118

[52] US. Cl 260/294.8 G; 424/263; 260/310 R 51 Int. cm c07D'231/00 [58] Field of Search 260/294.8 G

[56] References Cited UNITED STATES PATENTS 3,847,929 11/1974 Denzel et al 260/296 H OTHER PUBLICATIONS Chemical Abstracts, Vol. 67, abst. no. w( 1967), (abst. of Troitskaya et al.). Korbukh et al., Zhur. Org. Khim. Vol. 9, pp. l2661272, (June 1973), (English equivalent, pp. 1294 to 1300 furnished).

[4 1 Sept. 2, 1975 Primary Examiner.lohn D. Randolph Attorney, Agent, or Firm-Lawrence S. Levinson; Merle J. Smith [5 7] ABSTRACT The new derivatives of sulfonyI-, sulfinyland sulfenylpyrazolo[3,4-b]pyridines have the general formula The novel compounds are useful as central nervous system depressants, antiinflammatory and diuretic agents. In addition, the new compounds increase the intracellular concentration of adenosine-3',5'-cyclic monophosphate.

14 Claims, No Drawings 1 NEW DERIVATIVES OF SULFONYb. SULFINYL- AND SULFENYL- l I'I-PYRAZOLO [3 ,4-B ]-PYRIDINES SUMMARY OF THE INVENTION This invention relates to new sulfonyl-, sulfinyland sulfenyl derivatives of lH-pyrazolo[3,4-b1pyridines, and salts of these compounds. These newcompounds have the formula R is hydrogen, lower alkyl, phenyl, phenyl-lower alkyl or furfuryl.

R is hydrogen, lower alkyl or phenyl.

R is hydroxy, lower alkoxy or a basic nitrogen group DETAILED DESCRIPTION OF THE INVENTION The lower alkyl groups referred to throughout the specification include straight or branched chain hydrocarbon groups containing l to 7 carbon atoms. Examples of the type of group contemplated are methyl, ethyl, propyl, isopropyl, butyl, tbutyl, etc. The lower alkoxy groups include the same moieties. Preferred are the l to 4 carbon groups, especially 1 to 2 carbon members.

Preferred embodiments of thisinvention are as follows:

R is hydrogen or lower alkyl, most preferably hydrogen or ethyl.

R is hydrogen or lower alkyl, most preferably hydrogen or methyl.

R is hydroxy or lower alkoxy, most preferably ethoxy, or a basic moiety with the substituents R and R representing hydrogen or lower alkyl, most preferably both R and R are hydrogen or R is hydrogen and R forms lower alkylamino, especially butylamino or see. butylamino.

R is lower alkyl; preferably methyl, or phenyl.

R is hydrogen or lower alkyl, most preferably methyl.

n is 0, l or 2.

The new compounds of formula I are produced by the following methods A -aminopyrazole of the formula prepared according to the procedure described in 2. f. Chemie 10, 386-388 (1970) is made to react with a haloacetoacetic acid ester of the formula II. o x

(wherein R is other than hydrogen and X is chlorine or bromine) by heating at a temperature of about -90 C, while distilling off the water formed by means of an appropriate solvent like benzene.

The resulting compound of the formula is treated with an alkali metal mercaptide or an alkali metal salt of a sulfinic acid to give a compound of the formula wherein n is O or 2.

When R is hydrogen the S-aminopyrazole of formula II is made to react with an acrylic acid derivative of the formula (VI) S-R 1| ROCH=C [Oln COOR wherein R is lower alkyl.

Compounds of formula V wherein n is 0, l or 2 may alternatively be produced by reaction of a compound of the formula (lVa) with the appropriate sulfenic,-sulfinic or sulfonic acid halide, e.g., I

compound of the formula i A compo und'of the formula I l R O-lower alkyl A product of formula lb is then produced by reacting the compound, of formula lc with an alkali metal alcoholate.

Compounds of the formula with an amino group in the 4-position are produced by reacting either a compound of formula lb or formula [c with the amine of the formula (vm RG wherein R and R are the same as previously described. Sometimes it is advantageous to make use of an autoclave.

Compounds of formula la, b and c in which n is 1 are produced by oxidizing a product of formula 1a,] or c in which n is with an oxidizing agent like sodium periodate, a hydroperoxide,'potassium permanganate, selenium dioxide or the like; Compounds of formula Id in which n is l areproduced by reacting compounds of formulalb and la (with n l) with an amine 'as previously described.

According to a modification of the foregoing procedure, a product of formula I wherein R is hydrogen is produced. By this modification, a S-aminopyrazol'e of formula II, wherein R is a heteromethyl group, is used. This starting material has the formula (IIa) 1'2 about 160C. yielding the compound of the formula H l N 1 H 0- lower alkyl wherein R is hydrogen. This type of compound is a suitable one to be converted to derivatives carrying a substituent in the 4-position wherein R is other than lower alkoxy.

The compounds of formula l form salts which are also part of this invention. The salts include acidaddition salts, particularly the non-toxic, physiologically acceptable ones. The bases of Formula I form acid addition salts by reaction with a variety of inorganic and organic acids. Examples of acid addition salts are the'hydrohalides (especially the hydrochloride), sulfate, nitrate, phosphate, oxalate, tartrate, malate, citrate, acetate, ascorbate, succinate, benzenesulfonate, toluenesulfonate, eyclohexanesulfonate, etc. The acidaddition salts frequently provide a convenient means for isolating the product, e.g., by forming and precipitating the salt in an appropriate menstruum in which the salt is insoluble, then after separation of the salt, neutralizing with a base such as barium hydroxide or sodium hydroxide, to obtain the free base of formula I. Other salts are then formed from the free base by reaction with an equivalent of the appropriate acid.

The novel compounds of this invention are central nervous system depressants, and are useful as ataractic agents. They find further utility as antiinflammatory agents. They can be used, for example, in mice, cats, rats, dogs and other mammals. For this purpose, a compound or mixture of compounds of formula I, or nontoxic. physiologically acceptable acid addition salt thereof, is administered orally or parenterally in a conventional dosage form such as tablet, capsule, injectable or the like. A single dose, or preferably 2 to 4 divided doses, may be provided on a basis of about 1 to 50 milligrams per kilogram per day, preferably about 2 to 15 mg/kg/day. These are conventionally formulated in an oral or parenteral dosage form by compounding about to 25 milligrams per unit of dosage with conventional vehicle, excipient, binder, preservative, stabilizer, flavor or the like as called for by accepted pharmaceutical practice. As antiinflammatory agents they can be used topically by formulating a conventional topical composition such as a cream or lotion containing the active substance in a concentration of about 0.1 to 0.3 percent by weight.

The new compounds also increase the intracellular concentration of adenosine-3',5-cyclic monophosphate. The use of about 1 to 25 mg/kg/day in a conventional dosage form as described above alleviates the symptoms of asthma.

The following examples are specific embodiments of the invention. All temperatures are recorded on the centigrade scale.

EXAMPLE 1 a. 2-Chloro-3-[( 1-ethyl-5-pyrazolyl )amino 1 crotonic acid, ethyl ester 1 l l g. of S-Amino-l-ethylpyrazole (lMol.) and 164 g. of a-chloroacetoacetic acid ethyl ester are heated in 600 ml. of benzene at reflux temperature. The water formed is removed continuously by means of a water separator. Heating is continued until the theoretical amount of water has been formed (approximately 10 hours). After this time, the benzene layer is decanted from the viscous oil and evaporated to dryness. The oily residue is recrystallized from diethyl ether yielding 164 g. of 2-chloro-3-[( l-ethyl-5-pyrazolyl)amino]- crotonic acid ethyl ester, m.p. 4244.

b. 3-[( l-ethyl-5-pyrazolyl)amino]-2-(phenylsu1fonyl)crotonic acid ethyl ester 275 g. of 2-chloro-3-[( l-cthyl-5-pyrazolyl)amino]- crotonic acid ethyl ester lmol.) are dissolved in 1 liter of anhydrous dioxane and refluxed with stirring with 164 g. of sodium phenylsulfonate for 24 hours. After this time, the mixture is evaporated to dryness, the oily residue is dissolved in about 1 liter of ether and filtered. The ethereal solution is evaporated to dryness. The resulting product, 3-[(l-ethyl-5-pyrazolyl)amino]-2 (phenylsulfonyl)crotonic acid ethyl ester, is obtained as an oil which is used without further purification.

c. l-Ethyl-4-hydroxy--methyl-5-phenylsu1fonyl-1H- pyrazolo[ 3 ,4-blpyridine 36.3 g. of l-ethyl-S-pyrazolyl)amino]-2- (phenylsulfonyl)crotonic acid ethyl ester (0.1 M01) are treated in an oil bath at 240245 until no more alcohol distills off. (about 10 min.) The solution is cooled to room temperature and 50 ml. of methanol are added. The product, 1-cthyl-4-hydroxy-6-methyl-5- phenylsulfonyll H-pyrazolo 3 .4-b ]pyridine crystallizes, is filtered and recrystallized from butanol, yield EXAMPLE 2 l-Ethyl-4-ethoxy-6-methyl5-phenylsulfonyll H- pyrazolo[ 3,4-b ]pyridine EXAMPLE 3 4-Butylamino-1ethyl-6-methyl-5phenylsulfonyl- 1H- pyrazolo 3 ,4-b pyridine 8.8 g. of lethyl-4-ethoxy-6-methyl-5phenylsulfonylll-l-pyrazolo[3,4-blpyridine and 20 ml. of nbutylamine are refluxed for 12 hours.

After this period the excess butylamine is removed in vacuo and the residual 4-n-butylamino-1-ethyl-6- methyl-S-phenylsulfonyll H-pyrazolo[ 3 ,4-b lpyridine is recrystallized from ethylacetate, yield 8 g. (86%), m.p. 1 12-1 14. Treatment of this product with 1N hydrochloric acid in ethanol yields the hydrochloride salt.

4-Butylamino- 1 furfuryl-6-methyl-5phenylsulfonyllH-pyrazolo[3,4-blpyridine, m.p. l-l07, is produced by the above procedure by substituting 1- furfuryl4-ethoxy-6-methyl-5phenylsulfonyl- 1H- pyrazolo[3,4-b]pyridine as the starting material.

EXAMPLE 4 a. 3-[( 1-Ethyl-5-pyrazolyl)amino]-2-(phenylthio)erotonic acid ethyl ester 257 g. of 2-ehloro-3-[( l-ethyl-5-pyrazolyl)amino1- crotonic acid ethyl ester (lMol) and 132 g. of sodium thiophenolate are refluxed in 1 liter of anhydrous dioxane for 12 hours with stirring. The mixture is evaporated to dryness, the residue is dissolved in 500 ml. of ether and filtered. The filtrate is cooled to about 20 to 30 whereupon 3-[( 1ethyl-S-pyrazolyl)amino]-2- (phenylthio)crotonic acid, ethyl ester precipitates. The product is purified by recrystallization from petroleum ether, yield 270 g. (81%), m.p. 3637.

b. 1 -Ethyl-4-hydroXy6-methyl-5-phenylsulfenyl-1H- pyrazolo[ 3 ,4-b pyridine EXAMPLE 5 l-Ethyl-4-ethoxy-6-methylS-phenylsulfenyl- 1H- pyrazolo[ 3 ,4-blpyridine 3 .3 g. of 1-Ethyl-4-hydroxy-6-methyl-5- phenylsulfenyl- 1 H-pyrazolo[ 3,4-b]pyridine (0.01 M01), 2.8 g. of potassium carbonate 0.02 M01) and 3.1 g. of ethyl iodide (0.02 M01) are heated at 6070 in 20 ml. of dimethylformamide for hours with continuous stirring. The precipitate is filtered off and the fil trate is treated with 5 ml. of water. l-Ethyl-4-ethoxy-6- methyI-S-phenylsulfenyl-1H'pyrazolo[3 ,4-b]pyridine precipitates and is recrystallized from ethyl acetate, yield 2.5 g. (80%), m.p. 8687.

. 8 4-Ethoxy-1furfuryl-b-methyl-S-methylsulfenyll H- pyrazolo[3.4-b]pyridine, m.p. l0l103, is produced by the foregoing procedure from the product in Example 4b.

EXAMPLE 6 1-Ethyl-4-ethoxy-6-methyl-S-phenylsulfinyl- 1 H- pyrazolo[ 3,4-b1pyridine 3.1 g. of 1ethyl-4-ethoxy-6-mcthyl-5phenylsulfenyllH-pyrazolo[3,4-b]pyridine, 2.1 g. of sodium periodide, 20 ml. of methanol and 5 ml. of water are heated at 40-45 for 12 hours. The mixture is evaporated to dryness, the residue treated with 10 ml. of water and. extracted three times with 20 ml. portions of chloroform. The extract is dried over sodium sulfate, the solvent is distilled off and the crystalline residue is recrystallized from methanol to obtain l-ethyl-4-ethoxy-6- methyl-S-phenylsulfinyll l-l-pyrazolo 3 ,4-b pyridine yield 2.8 g. m.p. l36-138.

4-Ethoxy- 1furfuryl-6-methyl-5phenylsulfinyll H- pyrazolo[3,4-b]pyridine, m.p. l54l55, is produced by the above procedure by substituting 4-ethoxy-1- furfuryl-6-methyl-5phenylsulfenyll H-pyrazolo[ 3 ,4- blpyridine as the starting material.

4-Ethoxy- 1 ethyl-6-methyl-S-methylsulfinyll H- pyrazolo[3,4-b]pyridine, m.p. l17l20, is produced by the foregoing procedure by substituting 4-ethoxy-1- ethyl-6-methyl-5methylsulfenyll H-pyrazolo 3 ,4- b]pyridine as starting material.

EXAMPLE 7 4-Aminol ethyl-6-methyl-S-phenylsulfinyl- 1 H- pyrazolo[ 3 ,4-b pyridine 3.3 g. of 1ethyl-4-ethoxy-6methyl-S-phenylsulfinyl- 1l-l-pyrazolo[3,4-b1pyridine (0.01 M01) are dissolved in 50 ml. of butanol. 50 ml. of concentrated aqueous ammonia are added and the mixture is heated for 20 hours at in an autoclave. The solvent is removed in vacuo and the residue is recrystallized from a dimethylformamide-water mixture to obtain 4-amino- 1-ethyl-6-methyl-5phenylsulfinyll H-pyrazolo[ 3 ,4- b]pyridine, yield 17 g. (63%), m.p. 248250.

4-Aminol -ethyl-6-methyl-5phenylsulfonyll H- pyrazolo[3,4-b]pyridine, m.p. l84l86, is produced by the foregoing procedure by substituting l-ethyl-4- ethoxy-6-methyl-5phenylsulfonyll H-pyrazolo[ 3 ,4- blpyridine as the starting material.

4-Butylaminolethyl-6-methyl-S-phenylsulfinyll H- pyrazolo[3,4-b]pyridine, m.p. 99l 02, is produced by the foregoing procedure by substituting l-ethyl-4- ethoxy-6-methyl-5-phenylsulfinyll H-pyrazolo[ 3 ,4- b]pyridine as the starting material.

4-Aminol ethyl-6-methyl-5methylsulfinyl-l H- pyrazolo[3,4-b]pyridine, m.p. 176-180, is produced by the foregoing procedure by substituting 1-ethyl-4- ethoxy-o-methyl-S-methylsulfinyll H-pyrazolo[ 3 ,4 b[pyridine as the starting material.

EXAMPLE 8 V a. 3- l-Ethyl-5-pyrazolyl )amino l-2-methylthiocrotonic acid, ethyl ester 257 g. of 2-chloro-3-[( l-ethyl-5-pyrazolyl)amino]- crotonic acid ethyl ester (1 M01) and 70 g. of sodium ethyl mercaptide are refluxed for 12 hours in 1 liter of anhydrous dioxane with stirring. After this time, the

mixture is evaporated to dryness, the oily residue is dissolved in about 1 liter of ether and filtered. The solvent is removed in vacuo and the resulting product, 3-[( 1- ethyl-S-pyrazolyl )amino -2-methylthiocrotonic acid, ethyl ester, is obtained as an oil which is used without further purification.

b. l Ethyl-4-hydroxy-6-methyl-5-methylthiol H- pyrazolo[3,4-b]pyridine The oily product from part a is heated in an oil bath at 230-240 for about minutes. After this time, the mixture is cooled and about 300 ml. of methanol are added. l-Ethyl-4-hydroxy-6-methyl-5-methylthio- 1 H- pyrazolo[3,4-b]pyridine crystallizes and is purified by recrystallization from butanol, yield 85 g., m.p. 253-255.

EXAMPLE 9 1-Ethyl-4-ethoxy-6-methy1-5-methylthio-1H- pyrazolo 3 ,4-b pyridine EXAMPLE 10 a. 2-Chloro-3- l-furfury1-5-pyrazolyl)amino]crotonic acid ethyl ester 163 g. of S-amino-l-furfurylpyrazole (1 M01) and 164 g. of cx-chloroaceto acetic acid ethyl ester are heated in 600 ml. of benzene at reflux temperature. The water formed is continuously removed by means of a water separator. When the theoretical amount of water is distilled off, the benzene layer is decanted from the viscous oil at the bottom of the flask. The benzene is evaporated in vacuo and the residue is recrystallized from diethyl ether yielding 225 g. of 2-chloro-3-[( lfurfuryl-S-pyrazolyl)amino]crotonic acid ethyl ester (73%), mp. 36-38.

b. 3-[( l-Furfuryl-S-pyrazolyl )amino]-2-phenylsulfonylcrotonic acid ethyl ester 309 g. of 2-chloro-3-[( 1-furfuryl-5-pyrazolyl- )aminolcrotonic acid ethyl ester 1 M01) and 164 g. of sodium phenylsulfonate are refluxed for 24 hours in 1 liter of anhydrous dioxanc. The solvent is removed in vacuo and the residue is dissolved in about 1 liter of ether. The inorganic precipitate is filtered off and the filtrate cooled to about to "30. 3-[( l-furfuryl-S- pyrazolyl)amino1-2-phenylsulfonylcrotonic acid ethyl ester crystallizes and is filtered off, yield 345 g. (83%), m.p. 81-82.

3- 1 -furfuryl-5-pyrazolyl )amino l-2-phenylsulfonylacrylic acid ethyl ester (m.p. 123-125) is similarly produced from S-amino-l-furfitrylpyrazole and 3-ethoxy-2-phenylsulfonylacrylic acid ethyl ester.

0. 1-Furfuryl-4-hydroxy-6-methyl-5-phenylsulfonyll H- pyrazolo[ 3 ,4-b pyridine 208 g. of [(1-furfuryl-5-pyrazolyl)aminol-2- phenylsulfonylcrotonic acid ethyl ester (0.5 M01) are heated at 240245 while distilling off the alcohol formed. After cooling to room temperature, 200 ml. of methanol are added. 1-Furfuryl-4-hydroxy--methyl-5- phenylsulfonyl-1H-pyrazolo[3,4-b]pyridine crystallizes and is filtered and recrystallized from butanol, yield 95 g. (51%), mp 187189.

l-Furfuryl-4-hydroxy-6-methyl-S-phenylthio- 1H- pyrazolo[3,4-b]pyridine, m.p. 220221, is produced by the foregoing procedure by substituting 3-[( lfurfuryl-S-pyrazolyl )amino]-2-phenylthiocrotonic acid ethyl ester as the starting material.

EXAMPLE 1 1 1-Furfuryl-4-ethoxy-6-methyl-5-phenylsulfonyl- 1 H- pyrazolo[ 3 ,4-b ]pyridine 36.9 g. of 1-furfuryl-4-hydroxy-6-methyl-5- phenylsulfonyl-1H-pyrazolo[3 ,4-b ]pyridine (0. 1 Mol 20.7 g. of potassium carbonate, 23.2 g. of ethyl iodide (0.15 M01) are heated with stirring in 100 ml. of dimethylformamide for 20 hours at The mixture is filtered hot and 10 ml. of Water are added. 1-Furfuryl-4- ethoxy-6-methyl-S-phenylsulfonyll H-pyrazolo[ 3 .4- blpyridine crystallizes, yield 30 g. mp 177179 (butanol).

4-Ethoxy-1-furfuryl-6-methyl-5-phenylthio-1H- pyrazolo[3,4-b]pyridine, m.p. 109-l1 1, is produced by the above procedure by substituting l-furfuryl-4- hydr0xy-6-methyl-5-phenylthiol l-l-pyrazolo 3 ,4- b]pyridine as the starting material.

EXAMPLE 12 4-Ethoxy-6-methyl-5-phenylsulfonyl-1H-pyrazolo[3 ,4- b pyridine 3 .9 g. of 1-furfuryl-4-ethoxy-6-methyl-5 phenylsulfonyl-1H-pyrazolo[3,4-b]pyridine (O. 1 M01) and 1.2 g. of selenium dioxide (0.01 1 Mol) are refluxed in diglyme for 2 hours. The selenium is filtered off and the filtrate evaporated to dryness. On addition of 10 ml. of ether, 4-ethoxy-6-methyl-5phenylsulfonyl-ll-lpyrazolo[3,4-b]pyridine crystallizes, yield 2.0 g.

' (63% m.p. 264-266 (butanol).

EXAMPLE 1 3 4-Amino-6-methyl-5-phenylsulfonyll H-pyrazo1o[ 3,4- b ]pyridine 3.2 g. of 4-ethoxy-6-methyl-5-phenylsulfonyl-1H- pyrazolo[3.4-b]pyridine (0.01 M01), ml. of concentrated aqueous ammonia and 20 ml. of butanol are heated in an autoclave for 10 hours at The resulting mixture is evaporated to dryness and the residue is recrystallized from butanol to obtain 4-amino-6- methyl-S-phenylsulfonyl- 1 H-pyrazolo[ 3 ,4-b]pyridine, yield 1.9 g (63%),m.p. 248-250.

EXAMPLE 14 a. 3-( l-Ethylpyrazolyl--amino)crotonic acid ethyl ester 1 l l g. of l-Ethyl-S-aminopyrazole 1 Mol), 130 g. of

acetoaeetic acid ethyl ester and l g. of p-toluene sul- I fonic acid are refluxed in 1 liter of benzene. The water formed is removed by a water separator. After 2 hours, the reaction is finished and the solvent is distilled off.

The oily residue is dissolved in about 500 ml. other. 3- (l-ethylpyrazolyl-5-amino)crotonic acid ethyl ester solidifies on cooling, yield 200 g. (89%), m.p. 7576.

b. l-Ethyl-4-hydroxy-6-methyl-5-methylsulfonyll H- pyrazolo[3,4-b]pyridine l l 1.5 g of 3-( l-Ethylpyrazolyl-5-amino)crotonic ethyl ester (0.5 Mol) is added to a suspension of 26.4 g. of sodium hydride (0.55 M01) in 1 liter of anhydrous dioxane. The mixture is kept at 60 for minutes with I stirring. After this time, 57 g. of methanesulfonic acid chloride is added dropwise. Refluxing is continued for 24 hours. -Ethylpyrazolyl-solvent is distilled off and the resulting oil carefully acidified with acetic acid. Water is added and the oil extracted 3 times with 200 ml. portions of chloroform. Drying and evaporation of the solvent yields crude 3-( l-ethylpyrazolyl-S-amino )2- methylsulfonyl crotonic acid ethyl ester which is heated inan oil bath at 240 until no more alcohol distils off. After cooling to room temperature, 200 ml. of methanol are added. The product, 1-ethyl-4-hydroxy-6- methyl-S-methylsulfonyll l-l-pyrazolo[ 3 ,4-b]pyridine, is'recrystallized from butanol, yield 55 g. (43%), m.p. 226227.

EXAMPLE l5 l-Ethyl-4-ethoxy-6-methyl-S-methylsulfonyll H- pyrazolo 3,4-b lpyridine EXAMPLE 16 4-sec.Butylaminol -ethyl-6-methylE5-methylsulfonyllH-pyrazolo[3,4-b]pyridine 2. 8 g. of l-Ethyl-4-ethoxy-6-methyl-5 methylsulfonyll H-pyrazolo[3,4-b lpyridine (0.01 Mol) and 50 ml. of sec. butylamine are refluxed for 24 hours. After this time, the excess sec. butylamine is removed in vacuo and the residue is recrystallized from methanol to obtain 4-sec.butylamino- 1,-ethyl-6-methyl- 5-methylsulfonyll H-pyrazolo[ 3 ,4'-b lpyridine, yield 2.5 g. (79%), m.p. l39140.

EXAMPLE l7 4-Hydr0xy-l ,3,6-trimethyl-5-phenylsulfonyll H- pyrazolo[ 3,4-b]pyridine' By following the procedure of Example 1 but substituting 5-amino-l,3-dimethylpyrazole as the starting 4-hydroxy-1,3,6-trimcthyl-5- is obmaterial in part (a), phenylsulfonyllH-pyrazolo[ 3,4-b]pyridine tained.

' EXAMPLE 1:;

4-Propoxyl ,3,6-trimethyl-5-phcnylsulfonyll H- 'pyrazolo[ 3 ,4-b lpyridine By following the procedure of Example 2 using the product of Example 17 and propyl iodide instead of ethyl iodide, 4-propoxyl ,3 ,6-trimethyl-5- phenylsulfonyl-1H-pyrazolo[3,4-b]pyridine is obtained.

EXAMPLE 19 4-Diethylaminol -ethyl-6.-methyl-5-methylsulfonyllH-pyrazolo[ 3 ,4-b pyridine By following the procedure of Example l6 but substituting diethylamine for the sec.butylamine, 4- diethylaminol -ethyl6-methyl-S-methylsulfonyll H- pyrazolo[3,4-b]pyridine is obtained.

EXAMPLE 20 4-Mcthylaminol -ethyl-6-methyl-S-phnylsulfinyll H- I pyrazolo[ 3,4-b]pyridine By following the procedure of Example 7 but substituting methylamine for ammonia, 4-methylamino-lethyl-6-methyl-5-phenylsulfinyll H-pyrazolo[ 3,4- b]pyridine is obtained.

' EXAMPLE 21 4-Amino-6-methyl-3-phenyl-S-phenylsulfonyll H pyrazolo[ 3,4-b1pyridine By substituting 5-amino-1-furfuryl-3-phenylpyrazole for the S-aminol-furfurylpyrazole in part (a) of Example l0, and proceeding as in parts (b) and ('c) of that example and also proceeding as in Examples ll l2 and 13, the 3-phenyl analogs of each of the products is obtained, with 4-amino-6-methyl-3-phenyl-5- phenylsulfonyl-ll-l-pyrazolo[3,4-b]pyridine as the final product.

EXAMPLE 22 1 ,6-Diethyl-4-ethoxy-5 phenylsulfonyl- 1H- pyrazolo[ 3 ,4-b pyridine v A By substituting 2-chloro-3-oxopentanoic acid ethyl esterfor the oz-chloro-acetoacetic acid ethyl ester in part (a)'of Example 1 and proceeding through parts (b) and (c) and Example 2, l,6-diethyl-4-ethoxy-5- phenylsulfonyll H-pyrazolo[3 ,4-b lpyridine is obtained.

EXAMPLE 23 4-Hydroxy-6-methyll-propyl-5-methylsulfonyll H- pyrazolo[3,4-b]pyridine By substituting S-amino-l-propylpyrazole as the starting material in part (a) of Example 14,4-hydroxyo-methyll -propyl-5-methylsulfonyll H-pyrazolo[ 3 ,4- b]pyridine is obtained.

EXAMPLE 24 l ,3-Diethyl-4-hydroxy-6-methyl-5-phenylsulfonyll H- pyrazolo[ 3 ,4-b pyridine By substituting S-amino-l,3-diethylpyrazole as, the starting material in part (a) of Example l,-' l,3-diethyl- 13 4-hydroxy-6-methyl-S-phenylsulfonyl-1H- pyrazolo[3,4-b]pyridine is obtained.

EXAMPLE 25 l-Phenyl-4-hydroxy-6-methyl-5-phenylsulfenyll H- pyrazolo[3,4-b]pyridine By substituting 2-chloro-3-[(l-phenyl-S-pyrazolyl- )aminolcrotonic acid ethyl ester for the starting material in part (a) of Example 4, l-phenyl-4-hydroxy-6- methyl-5-phenylsulfenyll H-pyrazolo- 3 ,4-b ]pyridine is obtained.

EXAMPLE 26 4-Amino-6-methyll -phenyl-5-phenylsulfinyl- 1 H- pyrazolol 3,4-b pyridine By utilizing the product of Example 25 and following the procedures of Examples 5, 6 and 7, 4-amino-6- methyll -phenyl-5-phenylsulfinyll H-pyrazolo[3 ,4- b]pyridine is obtained.

EXAMPLE 27 l-Benzyl-4-hydroxy-6-methyl-5-phenylsulfonyl-1H- pyrazo1o[ 3,4-b ]pyridine By substituting S-amino-l-benzylpyrazole for the starting material in part (a) of Example 1, l-benzyl-4- hydroxy-6-methyl-5-phenylsulfonyll H-pyrazol[ 3 ,4- blpyridinc is obtained.

EXAMPLE 28 l-Benzyl-4-dimethylamino-6-methyl-5-phenylsulfonyllH-pyrazole 3 ,4-b pyridine By utilizing the product of Example 27 in the procedures of Examples 2 and 3 and substituting dimethylamine for the n-butylamine, 1-benzyl-4- dimethylamino-6-methyl-5phenylsulfonyl-1H- pyraz0lo[ 3,4-b Ipyridine is obtained.

EXAMPLE 29 4-Butylamino-l-ethyl-6-phenyl-5-phenylsulfonyl-1H- pyrazolo[3,4-b jpyridine By substituting 2-chloro-2-benzoylacetic acid ethyl ester for the 2-chloroacetoacetic acid ethyl ester in part (a) of Example I and following the procedure of that example and Examples 2 and 3, l-ethyl-4-hydroxy-6- phenyl-S-phenylsulfonyl- 1 H-pyrazolol 3 ,4-b]pyridine, lethyl-4ethoxy-6-phenyl 5-phenylsulfonyl l H- pyrazolo[ 3,4-blpyridine, and 4-butylamin0- l -ethyl-6 phenyl-5phenylsulfonyl-1H-pyraz0lo[3 ,4-b lpyridine, respectively, are obtained.

What is claimed is:

l. A compound of the formula wherein R is hydrogen, lower alkyl, phenyl, benzyl or furfuryl; R is hydrogen, lower alkyl or phenyl; R is hydroxy, lower alkoxy or the group R, is lower alkyl or phenyl;

R is hydrogen, lower alkyl or phenyl;

R and R each is hydrogen or lower alkyl; 11 is 0, l

or 2; and physiologically acceptable acid addition salts thereof.

2. A compound as in claim 1 wherein R is hydrogen.

3. A compound as in claim 2 wherein R is hydroxy.

4. A compound as in claim 2 wherein R is lower alkoxy.

5. A compound as in claim 2 wherein R is amino.

6. A compound as in claim 2 wherein R is lower alkylamino.

7. A compound as in claim 3 wherein R and R each is lower alkyl, R is phenyl and n is 2.

8. A compound as in claim 3 wherein R is ethyl and R is methyl.

9. A compound as in claim 4 wherein R and R each is lower alkyl, R is phenyl and n is 2.

10. A compound as in claim 9 wherein R is ethyl, R is ethoxy and R is methyl.

11. A compound as in claim 6 wherein R and R each is lower alkyl, R, is phenyl and n is 2.

12. A compound as in claim 11 wherein R is ethyl and R is methyl.

13. A compound as in claim 6 wherein R,, R and R each is lower alkyl and n is 2.

14. A compound as in claim 13 wherein R is butylamino, R and R each is methyl and R is ethyl. 

1. A COMPOUND OF THE FORMULA
 2. A compound as in claim 1 wherein R2 is hydrogen.
 3. A compound as in claim 2 wherein R3 is hydroxy.
 4. A compound as in claim 2 wherein R3 is lower alkoxy.
 5. A compound as in claim 2 wherein R3 is amino.
 6. A compound as in claim 2 wherein R3 is lower alkylamino.
 7. A compound as in claim 3 wherein R1 and R5 each is lower alkyl, R4 is phenyl and n is
 2. 8. A compound as in claim 3 wherein R1 is ethyl and R5 is methyl.
 9. A compound as in claim 4 wherein R1 and R5 each is lower alkyl, R4 is phenyl and n is
 2. 10. A compound as in claim 9 wherein R1 is ethyl, R3 is ethoxy and R5 is methyl.
 11. A compound as in claim 6 wherein R1 and R5 each is lower alkyl, R4 is phenyl and n is
 2. 12. A compound as in claim 11 wherein R1 is ethyl and R5 is methyl.
 13. A compound as in claim 6 wherein R1, R4 and R5 each is lower alkyl and n is
 2. 14. A compound as in claim 13 wherein R3 is butylamino, R4 and R5 each is methyl and R1 is ethyl. 